1. Field of the Invention
The present invention relates to a bonding device, and in particular to a bonding device provided with a fastening member and a base to connect a printed circuit board to a tube or a liquid crystal module of an electronic device.
2. Description of the Related Art
In FIG. 1a, a conventional electronic device P1 such as a mobile phone has a printed-circuit board (PCB) 11, a liquid crystal module 13, a housing 15, a plurality of bolts 17, a first plate 111 and a second plate 131.
The PCB 11 is disposed on the first plate 111 and connected to the liquid crystal module 13 by a wire (not shown), and the liquid crystal module 13 is disposed on the second plate 131. A plurality of first positioning holes 113 are provided on the first plate 111, and a plurality of second positioning holes 133 corresponding to the first positioning holes 113 are provided on the first plate 111. The housing 15, provided with a plurality of posts 153 corresponding to the first positioning holes 113 of the first plate 111 and the second positioning holes 133 of the second plate 131, receives the first plate 111 and the second plate 131. The post 153 is cylindrical and hollow and a threaded portion 153b is provided on the inner wall of the post 153.
When aligning the first positioning holes 113 of the first plate 111 and the second positioning holes 133 of the second plate 131 to each post 153 of the housing 15, each bolt 17 passes through the second positioning holes 133 of the second plate 131 and the first positioning holes 113 of the first plate 111 and connects to the threaded portion 153b of the posts 153, respectively. Thus, the PCB 11 and the liquid crystal module 13 are mounted on the housing 15, i.e., the liquid crystal module 13 is properly disposed on the housing 15.
In FIG. 1b, an electronic device P2 has a printed-circuit board 11′, a liquid crystal module 13′ and a housing 15′. The PCB 11′ is provided with a plurality of first positioning holes 113′, and the liquid crystal module 13′ is provided with a plurality of second positioning holes 133′ corresponding to each first positioning hole 113′ of the PCB 11′. Several posts 153′ are formed on the housing 15′ each corresponding to the first positioning holes 113′ of the PCB 11′. The post 153′ is cylindrical and hollow, and a threaded portion 153′b is provided on the inner wall of the post 153′.
When aligning the second positioning holes 133′ of the liquid crystal module 13′ and the first positioning holes 113′ of the PCB 11′ to each post 153′ of the housing 15′, each bolt 17′ passes through the second positioning holes 133′ of the liquid crystal module 13′ and the first positioning holes 113′ of the PCB 11′ and connects to the threaded portion 153′b of the posts 153′, respectively. Thus, the liquid crystal module 13′ and the PCB 11′ are mounted on the housing 15′.
Based on the structure of the electronic devices P1 and P2, the positioning holes must be directly formed on s the liquid crystal module or the plate to support the liquid crystal module, and the posts corresponding to the positioning holes of the liquid crystal module or the plate must be formed on the housing of the electronic devices P1 and P2. This causes several problems.
First, because the posts are provided on the housing of the electronic devices P1 and P2, device dimensions cannot be efficiently reduced. As well, design and manufacture of the posts formed on the housing is time-consuming, as is assembly of the liquid crystal module, the PCB, the plates and the housing.
In general, there are two ways to form the post on the housing. One is to directly form an inner threaded portion on the inner wall of the hollow post, by, for example, injection molding, and the other is to dispose a nut or the like with an inner threaded portion into the post, by, for example, Thermo Compression (T/C) Bonding, embossing, or other means.
When the inner threaded portion is directly formed on the inner wall of the hollow post, especially for an electronic product with smaller volume, it is difficult to produce threads on the post in the smaller size. The housing is generally made of plastic and the post is integrally formed with the main body of the housing by injection molding. Thus, not only are difficulties encountered in production of threads on the inner wall of the plastic post, but the threaded portion of the post has an inherently short lifetime.
When performing Thermo Compression (T/C) Bonding or embossing to dispose the nut in the post, according to the second stated solution, a hole is provided in the post in advance. The hole is formed by drilling or integrally shaped when the housing is fabricated. The nut is then thermally pressed into the corresponding hole of the post manually, a time-consuming and costly process.